It is known to provide a data processing apparatus which processes vector operands havingmultiple data elements, which can perform corresponding data processing operation (often in parallel) on each data element of the vector operand. In some cases, a vector processing operation may be associated with control information indicating which data elements of the vector operand should be processed. The processing operation may be applied only to selected elements indicated by the control information, and not to other elements. The present technique seeks to improve processing performance when handling this type of vector processing operation.